Melvinia "Mattie" Shields, a young slave and an unknown white man who impregnated her are the great-great-great-grandparents of the first lady, the research found.

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The New York Times and a genealogist, Megan Smokenyak, followed a paper trail that revealed that Dolphus T. Shields, Michelle Obama's maternal great-great grandfather was born to Melvinia when she was about 15-years-old.

In1850, a South Carolina estate master left Melvinia, then a 6-year-old slave, to relatives in Georgia in a will that the Times decribed as "painstakingly divided." As a teenager, she was impregnated by an unidentified white man. A census lists Melvinia’s four children as mulatto, including her son Dolphus.

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Michelle Obama declined to comment on these findings, with aides saying the subject was too personal.